package com.cet.base;

import java.util.HashMap;

/**
 * @program: cet-practice
 * @description:
 * @author: 陈恩涛
 * @create: 2023-04-14 13:00
 **/
public class HashMapTest {
    public static void main(String[] args) {
        HashMap<String, Object> map = new HashMap<>();

        map.put(null, null);
        map.put("a", null);
        System.out.println(map.containsKey("aaa"));
        System.out.println(map.get("c"));
        System.out.println(map.get("a"));
        
    }
}
